Ignition Timing Control of Premixed Diesel Engine by Continuous Intake and Exhaust Variable Valve Timing

Premixed compression ignition is considered to be effective for the simultaneous reduction of soot and NOx emissions. However, it is a problem for control of ignition timing to be difficult. In this study, the variable valve timing mechanism (VVT) for the compression ignition timing control was applied to DI diesel engine. The compression ignition was carried out by temperature control in cylinder by using VVT. And, engine performance and exhaust emission were investigated about the influence of the valve timing and the fuel injection timing. As a result, it was proved that the control of ignition timing is possible by controlling early exhaust valve closing timing. Premixed compression ignition combustion at low load is possible by early exhaust valve closing timing. Also, NOx and soot were remarkably decreased by early fuel injection without increase of fuel consumption.